1. Field of the Invention
The present invention relates to a technology for obtaining an image having outstanding coloring ability and uniformity of color by applying an ink containing a coloring material and a liquid composition containing fine particles to a recording medium using an ink-jet system etc.
2. Related Background Art
The ink-jet recording method conducts recording by ejecting ink to apply the ink onto a recording medium such as paper. It is easy to realize a head having high-density multiple orifices, and that forms high-resolution and high-quality images at high speed by using an ink jet recording method where an ink droplet is ejected by the action of a bubble formed in the ink by applying thermal energy to the ink by using an electrothermal converter as an ejection-energy supply means as disclosed in, for example, Japanese Patent Publication Nos. 61-59911, 61-59912 and 61-59914.
In general, conventional inks for ink-jet recording contain water as a principal component, and in addition, a water-soluble solvent of a high boiling point such as glycol to prevent drying and clogging at orifices. When such an ink is used for recording on a recording medium, sometimes there arises problems such as insufficient fixation, and uneven image presumably due to the uneven distribution of a filler and/or a size on the surface of the recording medium such as paper. Besides, image quality as high as the silver salt photograph has recently become required for ink-jet recording, leading to intense technical demands for high image density, wide color reproduction range and enhanced color evenness on ink-jet recording.
Under such circumstances, various proposals have heretofore been made to stabilize the ink-jet recording process and to enhance the quality of articles recorded by the ink-jet recording process. One of the proposals on the recording medium is to coat the surface of a base paper of the recording medium with a filler and/or a size. For example, there has been disclosed a technique to form an ink receiving layer on the base paper by applying porous fine particles that adsorb a coloring material on the base paper as a filler. Recording media produced by using these techniques are now on market as the ink-jet coating paper etc.
Under such circumstances, in order to aim at stabilizing an ink-jet recording method, and improving quality of a recorded article by ink-jet recording method, various proposals have been made until now. Some of the typical examples will be summarized below.
(1) A method in which a volatile solvent and a penetrating solvent are added into an ink;
a method is disclosed in which a compound increasing penetrating property of a surface active agent etc. is added into an ink as means accelerating fixing ability of the ink to a recording medium in Japanese Patent Application Laid-Open No. 55-65269. Moreover, use of an ink comprising a volatile solvent as a main component is disclosed in Japanese Patent Application Laid-Open No. 55-66976.
(2) a method in which an ink and a liquid composition reacting with the ink are mixed on a recording medium;
a method is disclosed in which a liquid composition increasing quality of an image is applied on a recording medium before or after ejection of the ink for forming a recording image for enhancing image density of an image, for improving water proof property, and further for controlling bleeding.
Japanese Patent Application Laid-Open No. 63-60783 discloses a method in which a liquid composition containing a basic polymer is applied to a recording medium, and an ink containing an anionic dye is then applied thereto, thereby conducting recording. Japanese Patent Application Laid-Open No. 63-22681 discloses a recording method in which a first liquid composition containing a reactive chemical species and a second liquid composition containing a compound reactive with the chemical species are mixed on the recording medium. Further, Japanese Patent Application Laid-Open No. 63-299971 discloses a method in which a liquid composition containing an organic compound having two or more cationic groups per molecule is applied to the recording medium, and recording is then conducted with an ink containing an anionic dye. Japanese Patent Application Laid-Open No. 64-9279 discloses a method in which an acidic liquid composition containing succinic acid or the like is applied to a recording medium, and recording is then conducted with an ink containing an anionic dye.
Further, Japanese Patent Application Laid-Open No. 64-63185 discloses a method in which a liquid composition that can insolubilize dyestuff is applied to paper prior to application of an ink. Further, Japanese Patent Application Laid-Open No. 8-224955 discloses a method in which a liquid composition containing cationic substances different in molecular weight distribution range from each other is used together with an ink containing anionic compound. Japanese Patent Application Laid-Open No. 8-72393 discloses a method in which a liquid composition containing a cationic substance and finely ground cellulose is used together with an ink. In both publications, it is shown that the obtained image is excellent in image density, character quality, water fastness, color reproducibility and bleeding problem. Further, Japanese Patent Application Laid-Open No. 55-150396 discloses a method in which recording is conducted with a dye ink on a recording medium, and a water-proofing agent that forms a color lake with the dye is then applied to make the resulting recorded image water proof.
(3) A method in which an ink and a liquid composition containing fine particles are mixed on a recording medium;
in Japanese Patent Application Laid-Open No. 4-259590, a method is disclosed in which a nonaqueous recording liquid is adhered after a colorless liquid containing colorless fine particles comprising an inorganic material is applied on a recording medium, and in Japanese Patent Application Laid-Open No. 6-92010, a method is disclosed in which an ink containing pigments, water soluble resins, and water soluble solvents and water is applied on a recording medium after a solution containing fine particles or a solution containing fine particles and binder polymer. Both of the examples indicate that an image that exhibits a good printing quality and a good coloring ability is obtained not depending on the type of paper.
The present inventors has conducted repeated examinations for various kinds of the above described ink-jet recording technology, and as a result, found that in some case an excellent effect for each technical subject was confirmed, but other ink-jet recording characteristics were deteriorated in exchange for it. For example, it is well known that the above-described recording medium obtained by coating the surface of the base paper of the recording medium with a filler and/or a size (hereinafter referred to as coated paper) enables formation of high-quality images.
In general, in order to obtain an image of high saturation, it is known that the coloring material should be maintained in a monomolecular film state without aggregation on the surface of the recording medium, for which purpose the porous fine particles on the coated paper serve. However, in order to obtain images of both high density and high saturation with a given ink containing a coloring material, it is indispensable to form an ink-receiving layer as thick as the paper substrate is, covered with a large amount of the porous fine particles for a coloring matter, thus leading to the loss of the texture of the base paper. The present inventors thought that the reason why such a thick ink-receiving layer is required is that the coloring matter is not effectively adsorbed on the porous fine particles.
The following explanation is made assuming coated paper having one ink-receiving layer. FIG. 9 schematically illustrates a section of a coated paper in the vicinity of the surface thereof. In FIG. 9, reference numerals 901 and 903 indicate a base paper and an ink-receiving layer, respectively. The ink-receiving layer 903 comprises porous fine particles 905 and an adhesive (binder) 907 for immobilizing the particles. When an ink is applied to the ink-receiving layer 903, the ink penetrates into the voids between the porous fine particles 905 by capillarity to form ink-penetrated portions 909. As illustrated in FIG. 9, since the density of the porous fine particles in the ink-receiving layer varies locally, the mode of ink penetration by capillary phenomenon varies locally. Therefore, the coloring material cannot evenly contact with the surfaces of the porous fine particles in the course of ink penetration, so that the coloring material is not efficiently adsorbed by the porous fine particles.
Further, penetration of the ink is partially inhibited by the adhesive 907, and thus the ink-receiving layer 903 has portions into which the ink could not penetrate and which cannot contribute to coloring. For this reason, the adsorption of coloring material in a monomolecular state by the porous fine particles is not efficient compared with the particle amount in the conventional coated paper. As a result, a great amount of the porous fine particles is required to provide a high-quality image, impairing the texture of the base paper.
Furthermore, although fixing ability to a recording medium of an ink is improved by adopting the above described technology (1), occasionally, an image density is impaired or color reproduction range was also impaired, which is important for recording on regular papers or recording of color image. Moreover, according to the above described technology (2), since coloring material in an ink may be retained on a surface of a recording medium, a recorded article exhibiting a high image density may be obtained. However, probably because the coloring material is aggregated on a surface of the recording medium, in some cases a sufficient color reproduction range or sufficient saturation is not obtained. Moreover, in the above described conventional technology (3), although reforming of a surface state of a recording medium is realized by applying a solution containing fine particles, a brilliant image that exhibits an equivalent level to an image on a coated paper is not obtained. Furthermore, there are limitations in selection of a coloring material, and in the method of recordation, etc., and some problems are still left in the degree of flexibility, especially in an image formed by a nonaqueous recording liquid.
Thus, since some problems are left behind in the above described conventional methods, the present inventors have come to recognize that a novel ink-jet recording technology needs to be developed for a article recorded by ink-jet recording that exhibits the higher quality required in recent years. The present inventors, based on the above described new knowledge, found out that a reaction in a liquid-liquid state between a coloring material and fine particles is made possible by way of using fine particles with a function of adsorbing a coloring material, dispersing said fine particles and using them with an ink in a liquid state so that the coloring material is efficiently adsorbed or combined to said fine particles, and as a result, density of an image and saturation might be improved with a high reliability to attain the present invention.
Moreover, a further examination showed that when a liquid composition reacting with an ink is mixed on a recording medium, a quality (for example, coloring ability) of an image formed on a recording medium varies according to a recording condition of the ink and the liquid composition, and thus a specific recording condition is necessary to be satisfied in order to obtain a high coloring ability exhibiting a level equivalent to an image on a coated paper. Then, the present inventors have recognized a necessity of specifying a recording condition to provide an image with a high coloring ability. The present inventors found out that an image exhibiting a high coloring ability might be obtained using a certain specific recording condition especially in the case where a liquid composition was first applied and subsequently an ink was applied.
The present invention has been attained based on the above described new knowledge. And the present invention aims at obtaining a recorded article with high quality having a wider color reproduction range, excellent inhibition of bleeding, and outstanding uniformity and coloring ability, providing a recording condition required in order to obtain an image with the above described high coloring ability (an ink-jet recorded article) when recording is carried out by the ink-jet system or the like, and further providing a recording process and recording apparatus with which recording is carried out in the above described recording condition. Especially the present invention aims at obtaining an image exhibiting a high coloring ability in the case where a liquid composition is first applied and subsequently an ink is applied.
Moreover, the present invention aims at providing a method and an apparatus for manufacturing a recorded article in which an image exhibiting a high coloring ability is recorded.
In order to achieve the above-described objects, the present invention provides a recording method wherein, when recording is performed on a recording medium by use of an anionic or cationic ink and a liquid composition, the ink containing a coloring material, the liquid composition containing fine particles in a dispersed state, the surfaces of the fine particles being charged with a polarity opposite to that of the ink,
M, D, Ka, tw and t satisfy the relation of   t  ≤                    (                              5            4                    xc3x97                      MD            Ka                          )            2        +    tw  
where M (pg/xcexcm2) is the amount of the liquid composition supplied to the recording medium per unit area, D (%) is the concentration of the fine particles of the liquid composition, Ka (xcexcm/msec1/2) is the absorption coefficient of the liquid composition in the recording medium, tw (msec) is the time necessary for the liquid composition to moisten in the recording medium, and t (msec) is the time necessary for the ink to come into contact with the supplied liquid composition after the liquid composition is supplied to the recording medium.
The present invention also provides a method of performing recording on a recording medium by use of an ink containing a coloring material and a liquid composition containing fine particles to react with the coloring material in the ink, comprising:
a step of causing the ink to contact the liquid composition on the recording medium in liquid form in such a way that M, D, Ka, tw and t satisfy the relation of   t  ≤                    (                              5            4                    xc3x97                      MD            Ka                          )            2        +    tw  
where M (pg/xcexcm2) is the amount of the liquid composition supplied to the recording medium per unit area, D (%) is the concentration of the fine particles of the liquid composition, Ka (xcexcm/msec1/2) is the absorption coefficient of the liquid composition in the recording medium, tw (msec) is the time necessary for the liquid composition to moisten in the recording medium, and t (msec) is the time necessary for the ink to come into contact with the supplied liquid composition after the liquid composition is supplied to the recording medium, wherein
the coloring material is adsorbed on the surfaces of the fine particles in a monomolecular state by allowing the coloring material in the ink to contact fine particles in the liquid composition in the contact step, so that the fine particles having adsorbed the coloring material on the surfaces thereof aggregate to each other.
The present invention also provides a method of performing recording on a recording medium by use of an ink containing a coloring material and a liquid composition containing fine particles to be adsorbed on the coloring material, comprising:
a step of causing the ink to contact the liquid composition on the recording medium in liquid form in such a way that M, D, Ka, tw and t satisfy the relation of   t  ≤                    (                              5            4                    xc3x97                      MD            Ka                          )            2        +    tw  
where M (pg/xcexcm2) is the amount of the liquid composition supplied to the recording medium per unit area, D (%) is the concentration of the fine particles of the liquid composition, Ka (xcexcm/msec1/2) is the absorption coefficient of the liquid composition in the recording medium, tw (msec) is the time necessary for the liquid composition to moisten in the recording medium, and t (msec) is the time necessary for the ink to come into contact with the supplied liquid composition after the liquid composition is supplied to the recording medium, wherein
the coloring material keeping a monomolecular state is adsorbed on the surfaces of the fine particles by allowing the coloring material in the ink to contact fine particles in the liquid composition in the contact step, so that the fine particles having adsorbed the coloring material on the surfaces thereof aggregate to each other.
The present invention also provides a recording method wherein, when recording is performed on a recording medium by use of an anionic or cationic ink and a liquid composition, the ink containing a coloring material, the liquid composition containing fine particles in a dispersed state, the surfaces of the fine particles being charged with a polarity opposite to that of the ink,
recording is performed by supplying the ink after the liquid composition is supplied in such a way that fine particles having adsorbed a coloring material in a monomolecular state are present at least within a depth of 10 xcexcm from the surface of the recording medium.
The present invention also provides a recording method wherein, when recording is performed on a recording medium by use of an ink containing a coloring material and a liquid composition containing fine particles to be adsorbed on the coloring material,
recording is performed by supplying the ink after the liquid composition is supplied in such a way that aggregates formed by aggregation of the fine particles to each other, the fine particles having adsorbed a coloring material in a monomolecular state, are present at least within a depth of 10 xcexcm from the surface of the recording medium.
The present invention also provides a recording apparatus wherein, when recording is performed on a recording medium by use of an anionic or cationic ink and a liquid composition, the ink containing a coloring material, the liquid composition containing fine particles in a dispersed state, the surfaces of the fine particles being charged with a polarity opposite to that of the ink.
M, D, Ka, tw and t satisfy the relation of   t  ≤                    (                              5            4                    xc3x97                      MD            Ka                          )            2        +    tw  
where M (pg/xcexcm2) is the amount of the liquid composition supplied to the recording medium per unit area, D (%) is the concentration of the fine particles of the liquid composition, Ka (xcexcm/msec1/2) is the absorption coefficient of the liquid composition in the recording medium, tw (msec) is the time necessary for the liquid composition to moisten in the recording medium, and t (msec) is the time necessary for the ink to come into contact with the supplied liquid composition after the liquid composition is supplied to the recording medium.
The present invention also provides an apparatus for performing recording on a recording medium by use of an ink containing a coloring material and a liquid composition containing fine particles to react with the coloring, material in the ink, comprising:
means for causing the ink to contact the liquid composition on the recording medium in liquid form in such a way that M, D, Ka, tw and t satisfy the relation of   t  ≤                    (                              5            4                    xc3x97                      MD            Ka                          )            2        +    tw  
where M (pg/xcexcm2) is the amount of the liquid composition supplied to the recording medium per unit area, D (%) is the concentration of the fine particles of the liquid composition, Ka (xcexcm/msec1/2) is the absorption coefficient of the liquid composition in the recording medium, tw (msec) is the time necessary for the liquid composition to moisten in the recording medium, and t (msec) is the time necessary for the ink to come into contact with the supplied liquid composition after the liquid composition is supplied to the recording medium, wherein
the coloring material is adsorbed on the surfaces of the fine particles in a monomolecular state in the contact step by allowing the coloring material in the ink to contact fine particles in the liquid composition, so that the fine particles having adsorbed the coloring material on the surfaces thereof aggregate to each other.
The present invention also provides an apparatus for performing recording on a recording medium by use of an ink containing a coloring material and a liquid composition containing fine particles to be adsorbed on the coloring material, comprising:
means for causing the ink to contact the liquid composition on the recording medium in liquid form in such a way that M, D, Ka, tw and t satisfy the relation of   t  ≤                    (                              5            4                    xc3x97                      MD            Ka                          )            2        +    tw  
where M (pg/xcexcm2) is the amount of the liquid composition supplied to the recording medium per unit area, D (%) is the concentration of the fine particles of the liquid composition, Ka (xcexcm/msec1/2) is the absorption coefficient of the liquid composition in the recording medium, tw (msec) is the time necessary for the liquid composition to moisten in the recording medium, and t (msec) is the time necessary for the ink to come into contact with the supplied liquid composition after the liquid composition is supplied to the recording medium, wherein
the coloring material keeping a monomolecular state is adsorbed on the surfaces of the fine particles by allowing the coloring material in the ink to contact fine particles in the liquid composition in the contact step, so that the fine particles having adsorbed the coloring material on the surfaces thereof aggregate to each other.
The present invention also provides a recording apparatus wherein, when recording is performed on a recording medium by use of an anionic or cationic ink and a liquid composition, the ink containing a coloring material, the liquid composition containing fine particles in a dispersed state, the surfaces of the fine particles being charged with a polarity opposite to that of the ink,
recording is performed by supplying the ink after the liquid composition is supplied in such a way that fine particles having adsorbed a coloring material in a monomolecular state are present at least within a depth of 10 xcexcm from the surface of the recording medium.
The present invention also provides a recording apparatus wherein, when recording is performed on a recording medium by use of an ink containing a coloring material and a liquid composition containing fine particles to be adsorbed on the coloring material,
recording is performed by supplying the ink after the liquid composition is supplied in such a way that aggregates formed by aggregation of the fine particles to each other, the fine particles having adsorbed a coloring material in a monomolecular state, are present at least within a depth of 10 xcexcm from the surface of the recording medium.
The present invention also provides a method of manufacturing a recorded article with having an image being recorded on the recording medium thereof, comprising:
a step of recording an image by the recording method according to any one of claims 1 to 12.
The present invention also provides a recorded article having an image on the recording medium thereof, wherein the image includes fine particles having adsorbed a coloring material in a monomolecular state, at least within a depth of 10 xcexcm from the surface of the recording medium.
The present invention also provides a recorded article having an image on the recording medium thereof, wherein the image includes aggregates formed by aggregation of the fine particles to each other, the fine particles having adsorbed a coloring material in a monomolecular state, at least within a depth of 10 xcexcm from the surface of the recording medium.
In addition, in this specification, xe2x80x9ca reaction between a coloring material and fine particlesxe2x80x9d shall mean covalent bonds, as well as ionic bonds, and physical or chemical adsorption, absorption, adhesion and other interaction between both of a coloring material and fine particles.